Summary of Changes

• I felt the things you lacked the most are the things most important to a good EDH deck; ramp, card draw, and interaction
• I felt you ran too heavy on flicker effects, other protection spells, and on clones. These spells while good offer you little to no value when you are behind on board or after a board wipe since they require other creatures to create their value. By keeping the best and cutting down on volume we can improve other needed areas to help increase consistency.
• Reaper King obviously has a level of interaction already baked in with his ability but there will be many moments where you don't have him on the field and so you will need to contend with those moments with other interaction, so I have added some of that to this deck. I feel this could probably use some more interaction but at the expense of what I am uncertain, at some point you would start eating into your creatures which you don't want to do.
• This deck is pretty mana hungry so you will want to ramp up quickly to get to the point you can cast all the spells you want and protect reaper king and also just get him down early and take an early lead by heavily controlling your opponents (remember you can destroy lands, while shitty, is a valid win condition)
• This deck also seems to run into the problem often of being rather slow at times and adding card draw helps to move along your gameplan by giving you options and helping you to find that interaction to keep you in the lead.
• The mana base was also modified to this end to help make the mana base work for you as opposed to the other way around. Card draw and utility has been added in addition to better fixing.
• Some extra creatures have been added to help further synergize with your commander.

Explanation of Changes

Mana Base

• Looking at the existing deck you lean heavily towards blue already, with white and green following after.
• Since you are playing a 5 color deck and need a lot of mana, I chose to lean into green some more than before so that you could better ramp into the mana you need to support your game plan.
• This involved making changes to the ramp package will be discussed in the next section, but ultimately this meant that many of the duals and tri-lands would need to have a land type of Forest, with Island being a secondary type of main land type.
• Additionally, today I saw you crack a Misty Rainforest and this deck seems a great place to put it, so the other fetchable targets involve Islands.
• A cheeky inclusion here is Murmuring Bosk which is a Forest so it's fetchable through Misty or through the ramp package. Murmuring Bosk normally is reserved for treefolk tribal, but lucky for you there are changelings in the deck which can be revealed so that this land comes into play untapped, normally something you don't see on a tri land. The loss of life is not of concern.
• Spire of Industry is an any color land that only requires you to have an artifact out which with this deck is almost never a problem, therefore this is a must include.
• Buried Ruin and Academy Ruins are there to have some graveyard recursion in your land slot and since the scarecrows are all artifacts this will bring them back to your hand/top of deck. These can also be used if someone blows up your good artifacts like coat of arms.
• Malakir Rebirth, Valkaut Awakening, and Glasspool Mimic are all MDFC cards that are either a spell or a land. They fill a land slot and can be used as tap lands in the early game for when you need mana or more importantly can be used to great effect later in the game when you have plenty of mana to spare. This will help you feel like you are flooding out less which is always nice in commander, so imagine those times when you have gone "dammit another land" and replace that with "nice, I drew these instead of a land". Malkir is protection, Valakut is card draw, and Glasspool is another clone.
• Arcane Lighthouse was added because of the obvious, with Reaper King you sometimes need to get through hexproof or shroud.
• Finally, added some cycling lands because they also come with land types that let you fetch for them to color fix while again helping to prevent flooding. The triomes are also cyclable though you likely want to preserve these for color fixing.

Ramp

• Like I said you have access to green so why not use the best green ramp spells available with Nature's Lore, Three Visits, Farseek, and Skyshroud Claim which are all not too expensive at only a $3-$5 or so each.
• All of these except Farseek find lands with the Forest type which is why the majority of the duals have these as one of the types so you can ramp and fix at the same time.
• Farseek serves to fix you for anything that isn't green which you are more than happy to do, and there are other duals and triomes available that can be fetched with this card.
• Fellwar stone is a good 2 mana rock but I think you can run into the problem sometimes of having limited access to colors or not the right colors you need. I think subbing this with a Prismatic Lens offers you the 2 mana untapped rock for some ramp while also giving you the added utility of being able to filter mana. Sometimes you may find you don't have the exact color you need or not enough pips of a color you need to cast a spell. Early on fellwar runs into the issue of your opponents also not being color fixed yet and so you may not have access to the colors you need until later.
• Last changes that I made in the ramp section are adding Scaretiller and Wild Field Scarecrow. These two are not optimal or efficient, but that's okay because they are 1) more creature bodies and 2) synergize with your commander and his very powerful effect. These two also make for great blockers. These two are much better than Steve or Burnished Hart for this deck because of their synergy. Steve at his cost was replaced with better ramp of Nature's Lore and Three Visits.

Card Draw

• Alex and I both agree this is one of the areas where you lack a lot in your normal deck building process. To quote Alex from today; "it seems that card draw is how you win commander more than anything else" and I also think that holds true.
• You already had some nice pieces of card draw which I have left mostly in tact, though I added some more to help smooth out your games and increase consistency (and reduce salt) when playing.
• You already had a Demonic Tutor, but I figure why not go a couple steps further with Traverse the Ulvenwald and Fabricate. Traverse serves as ramp early game and a creature tutor for 1 mana late game and so it is a pretty flexible card overall. This can help you in a pinch if you need more ways to ramp or color fix or is just a better worldly tutor later on. Fabricate is particularly good since all of the scarecrows are artifacts and for the fact that there is some particularly useful artifacts in the deck such as Great Henge or Coat of Arms.
• Great Henge was added because you want to lean a bit toward the creature side to take advantage of Reaper King's effect (and because I know you have a few so why not put them to good use). Great Henge is so dang good since it's ramp, life gain, card draw, and creature buff all in one. If you still have these absolutely play these here. Great Henge is replacing Vanquishers Banner, so if you do not have them anymore you can keep the banner in.
• Fact or Fiction is no questions asked card draw. Yes you have to involve an opponent and hope they don't fuck you over, but honestly because you get to see both piles face up you just pick the set of cards that is best for the situation at hand and rarely this card flops. This is particularly useful after a board wipe or when you are behind because you don't have many other resources to lean on and this can be used politically too to get an opponent to give you what you want in exchange for (sexual) favors.
• Rishkar's Expertise is great card draw with Reaper King out since it'll draw you minimum 5 cards and let's you cast ANY 5 CMC or less permanent from your hand for free. This is also insane value and not that expensive of a card in terms of real life dollars. I think this is very worth playing since it basically refunds itself.
• Icon of Ancestry was added replacing Door of Destinies. Door is overall a pretty tough card to be good in a deck like this which has higher cost creatures and so few ETB triggers. Door is good in things like Elves or Humans that are puking out a lot of low CMC creatures and so it gets big quick. While Icon only gives a static +1/+1 buff it also has some repeatable card draw stapled to it that is well worth the drop in potential buffing.

Interaction

• The only interaction before was Masked Vandal and that is near unacceptable. Yes Reaper King has interaction stapled to him but you both have to work for that interaction and you have to have Reaper King in play. Because of his effect your opponents will try hard to keep him off the field and so you must account for the times in which he is not there to help you out.
• I added some counter magic which can be used to protect Reaper King when he is out or protect you when he is not. I chose some not as highly played ones that seemed to synergize well with the deck and so I think they are worth playing
• Dispersal Shield with Reaper King out basically is just counterspell, though you do have some other high CMC permaments such as Great Henge and Morphon that also offer a similar amount of just "No". I wanted to pick counterspells that didn't rely on two blue pips such as regular counterspell because of the fact that you are spread so thinly on your colors it could be tough to get a second blue pip.
• If you are fixing right (which hopefully you will be with the new ramp package and mana base) then Evasive Action essentially says counter spell unless the opponent pays 5 which is a heavy tax, higher than most. Even if you only have 3 land types out it just becomes mana leak which still isn't all that bad.
• Some other just good low cost removal in the form of Swords to Plowshares and Nature's Claim which can help you remove stuff if you don't have any scarecrows to spare.

Creatures

• I added Bloodline Pretender, Crossroads Candleguide, Graveshifter, and Irregular Cohort as good changelings that will help you out.
• Bloodline can become a big beefy
• Crossroads can remove some problematic cards from grave and in a pinch filter mana
• Graveshifter can return a creature to hand
• Cohort offers you two bodies which can give you two triggers with Reaper King. This also synergizes really with Shapesharer and another new addition in Sakashima's Will (more below)

Clones

• I kept the best of the clones, namely Sakashima and Spark Double since they work around the legend rule. Many of the other clones you had didn't help you here and so they were really not doing much unless Sakashima was already out.
• Speaking of, Sakashima's Will could be really awesome with a sakashima out copying a reaper king to make all your creatures Reaper Kings, then drop a scarecrow to basically board wipe. This is really cheeky and I think would need to be play tested to see if it actually works how I envision it, this can be replaced with another clone affect or just something different altogether.

Misc

• Number of flicker effects was cut down because I felt it would end up being dead cards in hand because you simply had too many. I kept the best ones in the list and added some other useful protection spells such as Heroic Intervention and Glaring Spotlight.
• Glaring Spotlight is awesome in this deck I feel, it is a redundant effect for Arcane Lighthouse in that it removes Hexproof from creatures when you want to hit them with Reaper King. It also has the added benefit of paying to give all your creatures hexproof and unblockability which can be used to finish off opponents.
• Removed Maskwood Nexus because I modified the deck to where everything is either a scarecrow or a changeling with the exception of Skyshroud Poacher so this effect isn't really needed any more. There is better tutor elsewhere and so this isn't needed to make cards like Forerunner of the Legion or Forerunner of the Siren to tutor changelings.